The objective of this project is to study the clinical applications of a new viewer for tomographic scans which allows the physician to examine multiple scan sections simultaneously in their proper relationship in all three dimensions. Test images provided on a prototype device clearly show stereopsis and parallax depth cues characteristic of a real three dimensional object. We are evaluating this device using x-ray CT and B-Scan ultrasound, also radiation therapy dose profiles, to determine the extent to which these data are more comprehensible when viewed in 3-D. Our primary objective in this reporting period is to design and begin constructing a viewing device suitable for testing and evaluation in a clinical environment.